1. Field of the Invention
The present invention generally relates to the art of switching mode power converters. More particularly, the present invention relates to PFC-PWM power converters.
2. Description of Related Art
Many power converters apply power factor correction (PFC) to correct the line current and subsequently generate a sinusoidal input current waveform that is in phase with the line voltage. Adding a PFC circuitry to the front end of a DC-to-DC power converter can prevent unnecessary power loss and heat dissipation from occurring in the power distribution system.
Unfortunately, traditional PFC circuits internally consume substantial amounts of power. This is especially significant under light-load and zero-load conditions. Because of this, traditional power converters often fail to meet government-mandated power conservation requirements.
The objective of the present invention is to provide an apparatus to reduce the power consumption of a PFC-PWM power converter under full-load and light-load conditions. Furthermore, in order to protect the PFC circuitry from over-stress operation and further reduce power consumption, the apparatus according to the present invention disables the power converter during brownout conditions.